Concussions: The Story, The Impact, and The Future

Following the 2010 Winter Olympics in which he led Canada to a gold medal with the game winning goal, Sidney Crosby was looking to lead his Pittsburgh Penguins to a Stanley Cup. However, this suddenly changed on January 1, 2011 when a blindside hit to Crosby’s head resulted in a concussion. The ensuing rehabilitation process was full of setbacks and doubt. It was not until January of the following year that doctors recognized Crosby’s injuries extended beyond his brain and into the soft tissue of his neck. Finally, Crosby returned to the ice in full form in March against the New York Rangers. How did concussions manage to baffle world-class physicians and sideline one of hockey’s greats?

The Center for Disease Control defines a concussion to be “a type of traumatic brain injury—or TBI—caused by a bump, blow, or jolt to the head or by a hit to the body that causes the head and brain to move rapidly back and forth” [9]. Contact and inertial forces are two major forces associated with these head injuries. Both forces can occur when the head is struck by an object, yet, inertial forces can also occur from rapid head accelerations without the need for an opposing object. Many studies have demonstrated that these inertial forces, which cause shear force on the brain, are responsible for the majority of concussive injuries [6].

These forces have deep neurologic impacts, especially on two types of cells: astrocytes and neurons. Astrocytes are glial cells. Glial cells are found in the brain and the spinal cord and provide insulation and support to neurons. According to Nature, astrocytes “contribute to [the] formation of the blood–brain barrier, participate in the maintenance of extracellular ionic and chemical homeostasis, are involved in the response to injury, and affect neuronal development and plasticity.” When mechanically impacted, astrocytes have shown changes in the “cytoskeleton, organelle function, and [have caused] biochemical cascades” [6]. Neurons, the other type of cell that has shown impacts from these forces, have shown changes in synaptic glutamate receptors, neurotransmission, and neural plasticity. Furthermore, these mechanical impacts on the brain have shown the capacity to activate pathways causing neuron death. Most importantly, repeated head injuries do not cause a superposition of brain damage, meaning that a second concussion could be more detrimental to neural cells than the first, and, likewise, a third concussion could be more detrimental than the second one.

According to the Weill Cornell Brain and Spine Center, concussions cannot be diagnosed with typical medical apparatuses like MRIs or CT scans [4]. Protocols for diagnosis include an interview to test for amnesia, a check for balance and coordination, and a neurological examination to test for reflexes. However, without a physical diagnostic capability, diagnosis can be subjective.

Mayo Clinic lists the possible, immediate symptoms of a concussion as a headache, temporary loss of consciousness, confusion, dizziness, or amnesia. Delayed symptoms that may appear only days after a concussion can include concentration difficulties, personality changes, sleep disturbances, and depression. Typically, symptoms for a concussion last for several days and disappear within a month.

The recommendation for a concussion is typically continuous rest until symptoms subside and then to gradually resume physical activity. However, in rare cases, symptoms continue to persist without remission; this is called post-concussion syndrome (PCS). There is currently no treatment for PCS, and in extreme cases symptoms may continue indefinitely, but doctors may recommend specific therapies to alleviate the worst recurring symptoms.

It is necessary to look beyond the physical effects of a concussion to the mental effects as well. After repeated concussions, athletes may be forced to retire from their sport which, in turn, can result in mental health issues. Nicknamed “Prime Time”, Deion Sanders is a two-time Super Bowl champion with success in both the National Football League (NFL) and Major League Baseball. Sanders who has suffered from has his own battle with depression has been vocal about discussing the mental health struggles of athletes after their careers have ended. Likewise, similar effects can occur for high school or college athletes who may be medically forced to retire from their sport. Until an integrated treatment for both the physical and mental symptoms of concussions is developed, the overarching effects cannot be cured.

Major sporting organizations including the NFL and the U.S. Club Soccer have instituted new protocols as they recognize the serious impacts of concussions In fact, the NFL has created a position for an independent neuro-trauma specialist to be present at all games. Furthermore, the NFL has also created a five-step “Return to Participation Protocol” with the first step requiring rest until concussion symptoms have cleared and the final step requiring clearance to play from both the team physician and an independent neurological consultant [7]. Additionally, the U.S. Club Soccer has created proactive rules to limit concussion injuries. For instance, they banned heading the soccer ball for players under the U11 division and limited heading for players in the U12/U13 divisions [5]. Although impactful in reducing concussions, these rules cannot prevent two soccer players from colliding after competing for a after a throw-in, Likewise, they cannot prevent a misjudged tackle, resulting in head-to-head contact. Therefore, in all reality, they cannot truly prevent concussions from occurring. Just as torn muscles and broken bones are an unfortunate element of sports, so too are head injuries. Only a better mechanism for recognizing, diagnosing, and treating concussions will serve as a final solution for athletes.

New solutions being developed for understanding the impacts of concussions include new computational models to better simulate impacts on the brain. These new models should help develop a better neurological understanding of what happens internally during a concussion. In addition, new engineering developments like new helmets for football have been designed to minimize the impact of head-to-head collisions [8]. On the neural side of the issue, scientists are working on creating synthetic neurons that can replace damaged ones in the brain (Simon). With the current pace of technology, new innovations will vastly improve the game for players on the pitch and for those players suffering from concussions. there could be a change in both the ability to design better equipment to prevent concussions on the pitch as well as develop new understandings and treatments for those afflicted.

Crosby and Sanders – athletes with such legendary ability that their names are synonymous with their respective games – both had their lives greatly changed by concussions. They, and so many other professional, collegiate, and high school athletes, share a legacy of concussions with an known impact. Increased computational modelling capabilities can hopefully improve the current understanding of concussions and serve as a replacement for the lack of empirical data. Moreover, new research concepts could allow for the creation of safer equipment for athletes on the field. For the well-being of the current and next generation of players, it will be necessary to translate this research into rapidly available clinical solutions.